The present invention relates to a hydraulic gun and particularly to a hydraulic gun adapted to return water to the source when not operated.
Hydraulic gun devices are available for delivering a jet of water through a restricted nozzle at high pressure for the purpose of cleaning various surfaces by means of the water jet alone or through use of sand or abrasives introduced into the water jet. These devices customarily include a normally open, trigger operated valve which dumps the flow of water on the ground until such time as the valve is closed and the water is forced to exit at high pressure through a restricted nozzle. In the non-operated condition of the gun, not only does water exit through the dump port, representing a considerable waste, but water also exits to a certain degree through the gun nozzle obscuring the operator's view of the surface or item being cleaned.
Reduction of water outflow in the non-operated gun condition is possible through elimination of the water dump port and provision of an unloading system in connection with the water supply pump. Thus, a return is made around the pump when a predetermined high pressure level is reached. However, the unloading device represents an additional item of equipment and expense, and the pump continues to operate at a high pressure, while there may still be leakage from the nozzle. Another device employs an electrical circuit for reducing pump pressure when the trigger is not operated, but this also represents an additional expense without elimination of water leakage.